Molding material and mold



c- 'z c Mata Oct. 13, 193'! umran srA'rss cRoss REFERENCE cm HUGO menus merrier, or srocnzonil, 'swimml xonnnwe xa'rnmnn m aroma In Drawing. Application filed January 25, 1830, Serial Io. 428,561, and in heden January 81, 1089.

When casting complicated objects one usu- A refractory mass as above stated how- I u ever, cannot be used for casting metals or metal alloys, of a hi h meltin point, such as precious metals an their a oys, steel and steel alloys, or other metals and alloys, whose melting points are 1200-1400 C. or higher, go For casting such metals or alloys, quite other qualities of the molding material are uired than for casting bronze or similar alloys. Be end an absolute constancy of volume an denseness throughout the whole 85 mass at the above named elevated temperature, a corresponding high refractcriness is required. The mass, moreover, must not contain water of crystallization, or other substances, which due to the elevated tempera;

' ture or due to the reaction caused by the contact with the metal, develop gases, which would give rise to porosity in the interior of the casting.

The present invention has for its object to as produce a molding material which can be used for casting bronze, or similar alloys, as well as metals or metal alloys having a considerably higher melting point.

According to the invention a molding ma- 0 terial is used for preparin the mold which comprises the following su stances:

1. 'One or more refractory substances such as quartz or substances having the same degree of refractoriness,

2. A cement, for

cement,

' Y 3. One or more silicates sintering at a lower temperature than quartz and cement,'preferabl water-glass.

- 'FhiamixturehaSbeenfoundtbcorrespond tributes in a hig instance Portland in many 'quirements or a molding material for molds used for casting metals, or metal alloys having high melting1 points; The quartz conde to the refractoriness of the mass. binder of the mass and for ainin the de sired consistency of volume eforefiiurning, and the silicate serves as a binding means during and after the burnin of the mold.

By the burnin any remain ers of wax arets to the above indicated re- 4 l e cement serves as a.

melted out, an the water of crystallization,

taken up by the cement during the binding, is driven out.

However, a mixture of the above mentioned constituents, although in many respects very suitable, has the inconvenience 'of solidifying so. quickly after havin been stirred in water, because of the rapi reaction, that difliculties arise in covering the wax model with the mixture. Moreover, a portion of the silicate (if a liquid silicate is used) is deposited on the surfaces of the mold in the form of needleshaped crystals, which during the subse uent burning of the mold are sintered toget er to a glass-hard, rough surface, impenetrable for air and any other gases, whereas the interior portions of the mass become spongy because of'the absence of silicate.

However, I have found, that if a suitable amount of glycerin is added to a mixture of the above mentioned substances, the reaction in the mass will be dam d, and the mixture will not solidify so quickly. Furthermore, the silicate will not crystallize on the surface during the bindin and dryin of the mass, but will rest equ distribu in the mass, which thus will stable and uniform throughout. Y

The proportions of the substances employed in the molding material may of course be varied within certain limits without afiecting the result.

My invention is also applicable to the pro-,

ductlon of cores for some molds, on account of their greater stability than the cores used at present, which usually are composed of a relatively slack mass consisting of a mixture of sand, clay,'ryemeal and molasses.

- summm WhatIclaimisz- 1. Moldindg material, consisting of a mixture of soli substances suspended in a suitable liquid, said mixture comprisin a y 5 refractory material, a cement, a 'cate and a glycerine.

2. Molding material consisting of a mixture of solid substancessuspended in a suit- I able liquid, said mixture comprising quartz, cement, a silicate and a glycerine.

3. Molding material consisting of a mixture of solid substances suspended in a suitable liquid, said mixture comprising quartz, cement, a silicate sintering at a lower temperature than quartz and cement, ,and a glycerine. v 1 4. Molding material consisting of a mixture of solid substances suspended in a suitable liquid, said mixture comprising quartz, cement, water-glass and a glycerine.

5. Casting molds and cores for sand molds prepared by the spreading of a liquid mass,

consisting of a mixture of a highly refractory materiaL'a cement, a silicate and a glyc- 25 erine, over a model of easily fusible material of the object to be cast, said liquid mass after binding, drying and the meltmg out of the model being burnt at a temperature of 900- 6. Casting molds and cores for sand molds prepared by the spreading of a li uid mass consisting of a mixture of quartz ortland cement, water-glass and a glycerme over a. wax model of theobject to be cast, said liquid 3 mass afier binding, dr 'ng and the melting out of the wax model mg burnt at a temperature of 900 1200C.

CARL GO MAGNUS ELMQUIST. 

